Vapor equilibrium models of accreting rocky planets demonstrate direct core growth by pebble accretion

The gaseous envelope of an accreting rocky planet becomes hot enough to sublimate silicates and other refractory minerals. For this work, we studied the effect of the resulting envelope enrichment with a heavy vapor species on the composition and temperature of the envelope. For simplification, we used the gas-phase molecule SiO to represent the sublimation of silicate material. We solved the equilibrium structure equations in 1D for planets in the mass range of $0.1$ to $3\,M_\oplus$. The convective stability criterion was extended to take the stabilizing effect of the condensation of SiO clouds into account. We assumed that the envelope is both in hydrostatic equilibrium and in vapor equilibrium with the underlying magma ocean. This means that pebbles do not undergo sublimation in the envelope and therefore survive until they plunge into the magma ocean. We find that the emergence of an inner radiative region, where SiO condensation suppresses convection, increases the pressure and temperature in the inner envelope compared to pure H$_2$/He envelopes once $M_\mathrm{pl} \gtrsim 0.3\,M_\oplus$. For $M_\mathrm{pl}>0.75\,M_\oplus$, the temperature and pressure close to the surface reach the supercritical point of SiO. The amount of SiO stored in the envelope is lower than the total planet mass for low mass planets. However, for $M_\mathrm{pl}>2.0\,M_\oplus$, all accreted pebble material must contribute to maintain the vapor equilibrium in the envelope. Therefore, the non-vapor mass of the planet ceases to increase beyond this threshold. Overall, our vapor equilibrium model of the planetary envelope allows for direct core growth by pebble accretion up to much higher masses than previously thought.Comment: 10 pages, 8 figures, accepted for publication in A&

Comparing apical bacterial leakage using two different obturation techniques in human upper incisors: An in vitro pilot study

The materials and techniques for root canal obturation is critical for treatment success. Cold lateral condensation is a widely used obturation technique, but core carrier techniques requiring heat has been developed to overcome disadvantages with the cold obturation techniques. GuttaCore is a relatively new and unstudied core carrier technique in vitro. The bacterial leakage test has been regarded as the most clinically relevant to compare obturation techniques, though the methodology has been questioned. No studies could be found comparing GuttaCore to lateral condensation using bacterial leakage models. Therefore, the aim of this in vitro study was to investigate the feasibility to compare cold lateral condensation and GuttaCore root filling techniques regarding bacterial leakage using a two-chamber system. 25 human upper incisors were selected into 2 experimental and 2 control groups. All teeth were mechanically cleaned and shaped using ProTaper Next rotary files (Dentsply Sirona, North Carolina, USA) and appropriate finishing hand files before obturation. The experimental groups were obturated by cold lateral condensation and GuttaCore techniques. A two-chamber system was set up to compare bacterial leakage, with Enterococcus faecalis as the bacterial mediator. Environmental contamination was investigated. The experiment lasted for 42 days. Three positive control and two GuttaCore specimens showed bacterial contamination. No specimens in lateral condensation group showed signs of leakage. One specimen showed environmental contamination. Within the limitations of this pilot study, a two-chamber system appears to be a feasible method to compare GuttaCore with other methods regarding bacterial leakage. To confirm our results, it needs future studies using a larger sample size

An Investigation of Courage, Emotion and Well-Being in Relation to Adventurous Activities

Adventurous outdoor activities often involve risk (Barton, 2006, p. 3) and higher purpose and therefore also courage to act. This study investigates possible differences in terms of emotions and courage-related measures between acting on or bypassing the call to courage. It also considers how well-being is affected by recalling and reflecting upon a courage-related experience. Through a mixed-methods questionnaire we captured qualitative and quantitative reports on an adventurous outdoor experience in which participants either acted or bypassed on a call to courage. Particpants were afterwards given the 7-point one-item Kemp Quality of Life Scale (Cheung & Lucas, 2014), which was also given to a control group. Our findings suggests recalling and reflecting upon adventurous activities has a positive effect on well-being. Both experimental groups rated well-being higher than control group, but the effect was only statistically significant for those who bypassed. Emotions, perceived risk, competence and desire to succeed can be used as reliable predictors for whether the participants acted or bypassed the activity. Those who acted reported stronger positive emotions, higher risk, stronger desire to complete and higher competence in relation to the activity than those who bypassed. Key words: Adventurous Activity, Risk, Courage, Well-Being, Emotion, Natur

The contribution of alternative habitats for conservation of plant species associated with threatened semi-natural grasslands

Conservation of species associated with semi-natural grasslands, a threatened habitat, is dependent on their ability to disperse between the few and fragmented patches remaining in the landscape. To maintain metapopulations dynamics and reduce the risk of regional extinction, it is essential to know whether other, more widespread, habitats can act as alternative habitat for the biodiversity associated with threatened habitats. Here, we study how four widespread habitat types in boreal landscapes—forest, permanent grassland, abandoned grassland and road verge—can contribute to the conservation of plant species found in semi-natural grasslands which is a species-rich ecosystem important for plant and pollinator diversity that has experienced extensive reduction, fragmentation and isolation. We compare richness of all vascular plants, insect-pollinated plants and semi-natural grassland specialists among habitat types in two regions is Norway where semi-natural grasslands are few and fragmented. Based on overlap in community composition and local species richness, road verges were the most promising alternative habitat for both insect-pollinated plants and semi-natural grasslands specialists. Several habitat specialist species were, however, only found in semi-natural grasslands and, for these species, no other habitat can be considered suitable as alternative habitat. Our results highlight that a holistic management perspective is needed to maintain biodiversity associated with semi-natural grasslands. Thus, both the protection of remaining patches of the primary, threatened habitats as well as management of widespread, alternative habitats in the landscape should be prioritized.publishedVersio

Negotiating Marriage: Before, During, After

What does it means to negotiate marriage? According to the Longman Synonym Dictio-nary the meaning of the word negotiate is complex: “Bargain, make a deal, go back and forth, give and take, compromise, meet halfway, agree on, settle differences, settle, come to terms, contract, conclude, complete, finish.” The Merriam-Webster Dictionary of Synonyms and Anto-nyms mentions that negotiating is connected to arrange: “Negotiate, arrange mean to bring about through an exchange of views and wishes and agreement reached by bargaining and compromise … . Negotiate suggests that the dealings are carried on by diplomatic, business, or legal agencies …”, and “Arrange implies dealings intended for the restoration or establishment of order of those carried out between private persons or their representatives… Arrange a marriage as they did long ago”.Couples today negotiate their relationships and their marriage contract over and over again. They ask: what are my obligations – what are yours? In what way shall we take care of our children? How much time shall we spend outside the home, and as wage earners? What is best, to share property and income, or to retain separate economy and property? There are many de-manding tasks to fulfill in a modern marriage. A critical point is this: Is there really time for sex? Problems and tensions easily arise. Perhaps husband or wife finds comfort in alcohol, or through involvement in extramarital affairs. Some husbands even ventilate their frustration by the use of violence against the spouse and the children. When communication and negotiating fail in the private sphere, there is a good chance that things may go so wrong that negotiating has to con-tinue in the public sphere. Marriage counseling could be a solution or the case ends up in court. As mentioned in the dictionary negotiating may imply that the dealings are carried out by legal agencies. The negotiating couple has to decide on child custody and on how to share belongings and property.The concept “negotiating” is central in the study of modern marriage. Is this also true when we are concerned with the institution of marriage in the early modern period? In the extensive literature on gender and the family in early modern Europe, the study of marriage trouble, marital breakdowns and marriage negotiations have received increasing attention and, as a consequence, the topic of how marriage was negotiated in a legal and public setting has also been explored. The context is then both legal history and history of family and of gender.What does it means to negotiate marriage? According to the Longman Synonym Dictio-nary the meaning of the word negotiate is complex: “Bargain, make a deal, go back and forth, give and take, compromise, meet halfway, agree on, settle differences, settle, come to terms, contract, conclude, complete, finish.” The Merriam-Webster Dictionary of Synonyms and Anto-nyms mentions that negotiating is connected to arrange: “Negotiate, arrange mean to bring about through an exchange of views and wishes and agreement reached by bargaining and compromise … . Negotiate suggests that the dealings are carried on by diplomatic, business, or legal agencies …”, and “Arrange implies dealings intended for the restoration or establishment of order of those carried out between private persons or their representatives… Arrange a marriage as they did long ago”.Couples today negotiate their relationships and their marriage contract over and over again. They ask: what are my obligations – what are yours? In what way shall we take care of our children? How much time shall we spend outside the home, and as wage earners? What is best, to share property and income, or to retain separate economy and property? There are many de-manding tasks to fulfill in a modern marriage. A critical point is this: Is there really time for sex? Problems and tensions easily arise. Perhaps husband or wife finds comfort in alcohol, or through involvement in extramarital affairs. Some husbands even ventilate their frustration by the use of violence against the spouse and the children. When communication and negotiating fail in the private sphere, there is a good chance that things may go so wrong that negotiating has to con-tinue in the public sphere. Marriage counseling could be a solution or the case ends up in court. As mentioned in the dictionary negotiating may imply that the dealings are carried out by legal agencies. The negotiating couple has to decide on child custody and on how to share belongings and property.The concept “negotiating” is central in the study of modern marriage. Is this also true when we are concerned with the institution of marriage in the early modern period? In the extensive literature on gender and the family in early modern Europe, the study of marriage trouble, marital breakdowns and marriage negotiations have received increasing attention and, as a consequence, the topic of how marriage was negotiated in a legal and public setting has also been explored. The context is then both legal history and history of family and of gender

Environmental factors controlling Gonyostomum semen blooms in a humic lake located close to a road

Algen Gonyostomum semen, har økt i utbredelse de siste tiårene i flere norske innsjøer, og er en art med forvaltningsmessige utfordringer og potensielt negative effekter for samfunnet. Økt utbredelse, mer dominans og flere oppblomstringer av algen, har i dag ingen enhetlig forklaring blant forskere. Derfor er det i dette studiet gjort analyser av flere kjemiske og fysiske variabler, for å kunne diskutere hvilke miljøfaktorer som er mest sentrale for å fremme oppblomstringer av algen. Til dette formålet blir Oppegårdstjern brukt, som er en dyp, humøs og vegnær innsjø i Viken fylke, som tidligere sesonger har hatt oppblomstringer av Gonyostomum semen. Det ble gjort feltarbeid fra mai til august 2021, hvor vannprøver fra ulike dyp ble samlet inn og analysert på laboratoriet. I tillegg ble det benyttet automatiske loggere til måling av temperatur og ledningsevne fra desember 2020 til slutten av feltperioden. Resultatene for klorid og ledningsevne viste at innsjøen ikke var betydelig påvirket av vegsalt, og at oppblomstringer av Gonyostomum semen i innsjøen ikke skyldtes vegsaltpåvirkning. Likevel kan det ikke utelukkes at større tilførsler av salt fra veger vil kunne føre til kjemisk sjiktning, som potensielt kan bidra til oppblomstringer av algen, både i Oppegårdstjern og i andre innsjøer. Sjiktning gir flere steder en fordel til Gonyostomum semen, hvis sjiktningene bidrar til et oksygenfattig miljø og oppkonsentrering av løste næringsstoffer i hypolimnion. Flagellene til algen gjør nemlig at den, i motsetning til de fleste alger, kan vandre til hypolimnion i sjiktede innsjøer og ta opp løste næringsstoffer. I Oppegårdstjern er innsjøen for dyp, og oppkonsentreringen av næringsstoffer for liten, til at algen kan benytte seg av næringsstoffer i hypolimnion. Miljøforholdene som var viktigst for å forklare oppblomstringer av Gonyostomum semen i Oppegårdstjern sommeren 2021, var trolig stabile værforhold og høye konsentrasjoner av løst organisk materiale, som bidro til en stabil temperatursjiktning. I tillegg var høy temperatur og næringstilgang i epilimnion sentralt. Dette kom frem av signifikante korrelasjoner mellom pigmentet som produseres av algen, og temperaturgradient, temperatur, og løst fosfor og nitrogen i innsjøen. Det bør derfor forventes økt utbredelse av Gonyostomum semen i takt med klimaendringer og mer «browning» av innsjøer i den kommende tiden. Utover gunstige miljøforhold, pekte de svært lave konsentrasjonene av næringsstoffer, samtidig som det var en kraftig oppblomstring av algen, på at Gonyostomum semen var godt tilpasset forholdene i Oppegårdstjern på grunn av sin fysiologi, mulig miksotrofisk næringsopptak, og biologiske interaksjoner med andre organismer.The alga Gonyostomum semen has increased its distribution in several Norwegian lakes in recent decades, and is a species with administrative challenges and potentially negative effects on society. Today, researchers have not concluded on a uniform explanation for its increase in distribution, dominance, and blooms. Through analyzes of several chemical and physical variables, this study aims to discuss which environmental conditions are most important to promote blooms of the alga. The lake Oppegårdstjern is used for this purpose. The site is characterized as a deep, humic lake close to a road located in Viken county, and blooms of Gonyostomum semen has occurred in this lake previous seasons. Fieldwork was carried out from May to August 2021, where water samples from different depths were collected and analyzed in the laboratory. In addition, automatic loggers were used to measure temperature and conductivity from December 2020 until the end of the field period. The chloride and conductivity results showed that the lake was not significantly affected by road salt, and that blooms of Gonyostomum semen in the lake were not caused by impacts from road salt. Nevertheless, it is possible that a larger supply of road salt could lead to chemical stratification, which could potentially contribute to blooms of the alga in Oppegårdstjern as well as in other lakes. In several places, stratification gives an advantage to Gonyostomum semen, if the stratification promotes oxygen depletion and accumulation of soluble nutrients in the hypolimnion. As opposed to non-flagellated species, the flagellated Gonyostomum semen can migrate down through the water column in stratified lakes and assimilate nutrients from the hypolimnion. In Oppegårdstjern the lake is too deep, with low accumulation of nutrients, making hypolimnetic nutrient assimilation impossible for the alga. The environmental conditions that seemed most important in explaining blooms of Gonyostomum semen in Oppegårdstjern the summer of 2021, were stable weather conditions and high concentrations of dissolved organic matter, which stabilized the thermal stratification. Additionally, high temperatures and nutrient supply in the epilimnion were important. This was made evident by significant correlations between the pigment produces by the alga and the thermal gradient, temperature, and phosphate and nitrate in the lake. Increased distribution of the alga is to be expected in accordance with future climate change and increased “browning” of lakes. In addition to favorable environmental conditions, the cooccurring low nutrient concentrations and massive algal blooms, points towards the alga being well-adapted to the conditions in Oppegårdstjern, because of its physiology, possible mixotrophic nutrient assimilation and biological interactions with other organisms.M-MIN

Spectroelectrochemical cell for in situ studies of solid oxide fuel cells

Solid oxide fuel cells (SOFCs) are able to produce electricity and heat from hydrogen- or carbon-containing fuels with high efficiencies and are considered important cornerstones for future sustainable energy systems. Performance, activation and degradation processes are crucial parameters to control before the technology can achieve breakthrough. They have been widely studied, predominately by electrochemical testing with subsequent micro-structural analysis. In order to be able to develop better SOFCs, it is important to understand how the measured electrochemical performance depends on materials and structural properties, preferably at the atomic level. A characterization of these properties under operation is desired. As SOFCs operate at temperatures around 1073 K, this is a challenge. A spectroelectrochemical cell was designed that is able to study SOFCs at operating temperatures and in the presence of relevant gases. Simultaneous spectroscopic and electrochemical evaluation by using X-ray absorption spectroscopy and electrochemical impedance spectroscopy is possible